Lucas playing for Brazil U20 in 2017
On 1 April 2016 Paquetá was called up for the first time to represent Brazil U20 in two friendly matches in Europe. He scored his first goal in his debut in a 2–1 win against England U20 on September 4.
In October 2016, he was called up for the Quadrangular de Seleções tournament, a friendly round-robin against the U20 squads of Ecuador, Uruguay, and Chile.
When he was 18, Paquetá was called to practice with the Brazil U23 team in preparation for the 2016 Summer Olympics. Coach Rogério Micale called some younger players born in 1997 and 1998, including Lucas, to participate in group training in hopes of them eventually competing in the 2020 Summer Olympics in Tokyo.
In 2018, he was selected to be one of the twelve alternatives for the Brazilian national team by coach Tite for the 2018 FIFA World Cup in Russia. Of the 35 players on the 23-man roster and provisional roster, Lucas Paqueta was the youngest.
On 17 August 2018, Paquetá was called for the first time for the Brazilian national team by manager Tite to play in friendly matches against United States and El Salvador in September. On 7 September, he made his debut with the national team, coming off the bench to replace Philippe Coutinho in the 71st minute during a friendly match against the United States. On 23 March 2019, he scored his first goal in a 1–1 friendly draw against Panama, wearing Brazil’s iconic No. 10 shirt.